1. Field of the Invention
This invention relates to industrial process control systems of the type employed with complex processes involving a large number of controlled process conditions such as temperature, flow-rate, and the like. More particularly, this invention relates to such systems having visual display means for presenting to the process operator or process engineer intelligible information to aid in exercising control over the process.
2. Description of the Prior Art
Industrial process control apparatus has evolved over the years from relatively simple individual controllers for respective process conditions to very large integrated systems including digital processing equipment. As the processes became more complex, there was greater need for acquiring process information in a more effective manner for better use by the process operators. Traditionally, complex control systems have included large control panels, thirty feet or so in length, with the process information and operator control devices located at various places along the panel.
It has been recognized that such a dispersed arrangement has serious drawbacks, and a number of proposals have been made for systems in which the information and controls are more effectively consolidated. One such prior system arrangement is disclosed in U.S. Pat. No. 3,971,000, issued on July 20, 1976, to N. O. Cromwell, and assigned to the assignee of this application. Although such systems have represented an important advance in the art, and have provided significant advantages, nonetheless it has been found that still further improvements are required to more fully meet the needs of the process industry, particularly the need for more effective man/process interface arrangements.